Unraveling the Global Warming Mitigation Potential from Recycling Subway‐Related Excavated Soil and Rock in China Via Life Cycle Assessment

Many cities across China are investing in subway projects, resulting in much subway construction activity, which has experienced a surge over the past decade. The construction activities inevitably cause a dramatic quantity of subway-related excavated soil and rock (ESR). How to manage it with minimal environmental impact on our urban ecosystem remains an open question. This present study evaluates global warming potential (GWP, expressed by CO 2 eq.) from different ESR recycling and landfilling scenarios via a life cycle assessment model based on primary field investigation combined with the LCA software database. The study results illustrate that recycling ESR can significantly reduce greenhouse gas emissions. In comparison with traditional construction materials, the scenarios found that a cumulative amount of 1.1-1.5 Mt (Million tonnes) of CO 2 eq. emissions could have been mitigated by using ESR generated between 2010 and 2018 to produce baking-free bricks and recycled baked brick. Using cost-benefit analysis, potential economic benefits from recycled sand and baking-free bricks are found to reach 9 million USD annually. The findings of this study could provide better recycling options for ESR-related stakeholders. It is important to mention is that there still much work to be done before this recycling work can be popularized in China. This article is protected by copyright. All rights reserved.